Digitrax Unit not shorting


E

+Eric

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I have a Digitrax DCC system, DB150 booster/command station.

I started having a lot of problems with it, very inconsistent running loco's. Now they won't run more than a few inches, however before they would run but I'd end up losing "control" over them. My layout is very new and in the very early stages.

The DB150 will not shut off with a short. Something buzzes, but the system doesn't shut off.

Everything, including the loco's run well on my grandfathers layout. I took my db150, controller and a loco down there and it ran fine, although admittedly I didn't check to see if it shorts outs. He uses a DB150 as well.

Any ideas? I have feeders about every 6 feet or so, on both lines. I just don't want to spin my wheels trying to come up with a solution, without seeing if someone with more experience has some insight, so I appreciate any help!

Do I need to try more feeders? Or maybe my layout is too big for one DB150? The bench is around 15x30'. I'd estimate we have somewhere between 130 and 150 feet of track down. Although, some of the other lines were isolated and not being powered at all atm. So closer to 130'. The bus is 12awg and the feeders are 24awg. To be fair and upfront, about 25 or so feet of track is feederless atm and power simply has to flow through the rails. I will start by wiring that section up like it should be, but like I said above, don't want to sit around throwing "solutions" at a problem, when maybe someone with more experience can point me in a good direction! I'm just worried about the DB150 not shutting off on an obvious short, like a quarter.

Thanks.
 
Have you checked the track voltage along all portions of your layout? If the control unit won't short, that indicates you have some section that must not be receiving full voltage. Especially check that section that doesn't have feeders. There's a voltage problems somewhere. DCC needs to have fairly consistent voltage throughout the whole layout or strange things can happen. You can also burn up decoders if they aren't getting enough voltage. Another thing to check is that the dual mode feature of your decoders are turned off. This means you set a VD that disables the engine from running on DC only. The decoder manual should have the correct setting. You can have the runaway problem when the engine gets confused on DCC and thinks it's on DC only and takes off. All this still goes back to your voltage issue. Find that and I think your problems will be over.
 
I think Jim's suggestion is the best place to start. I can't think of a reason for the command center not shutting down for a short unless something is damaged. Disconnect your track bus from command center and measure voltage...then momentarily short it. If it doesn't shut down then something internal has smoked. Also, think about what wiring you have done before this trouble came about: added feeders, track, turnouts, etc. Backtrack yourself and disconnect the last things you did until it clears. The symptoms are strange, but that happens sometimes. Its almost like something is crossed up, but not an actual short. (I run across that sometimes with block detection, but not on regular track layout.):)
 
Eric,

What are you using to provide power to the DB150? Does it provide 5+amps?

What gage buss wire are you using? How long is your power buss? I have found on my layout that once I got over 30' from the DB150 the quarter test would not work at the end of buss. Start near the DB150 and do the quarter test. Move progressively further away and see if it stops tripping? If it doesn't trip immediately, remove the quarter. You will need to add short circuit protection like a DCC Specialties PSX or a Digitrax PM42 to provide the short circuit protection at the distance.
 
UP2CSX said:
Have you checked the track voltage along all portions of your layout? If the control unit won't short, that indicates you have some section that must not be receiving full voltage. Especially check that section that doesn't have feeders. There's a voltage problems somewhere. DCC needs to have fairly consistent voltage throughout the whole layout or strange things can happen. You can also burn up decoders if they aren't getting enough voltage. Another thing to check is that the dual mode feature of your decoders are turned off. This means you set a VD that disables the engine from running on DC only. The decoder manual should have the correct setting. You can have the runaway problem when the engine gets confused on DCC and thinks it's on DC only and takes off. All this still goes back to your voltage issue. Find that and I think your problems will be over.
Click to expand...

Yeah, that seems very logical, the engines going into to DC mode. Thanks for the suggestions, I'll get those other feeders put in like they should be and start testing voltage at various points the proper way. When I was in the basement last night, prior to posting this message, I mistakenly thought you tested voltage between the two rails. Found out after trolling the digitrax support site, or maybe some other random site, that's not the case.

RexHea said:
I think Jim's suggestion is the best place to start. I can't think of a reason for the command center not shutting down for a short unless something is damaged. Disconnect your track bus from command center and measure voltage...then momentarily short it. If it doesn't shut down then something internal has smoked. Also, think about what wiring you have done before this trouble came about: added feeders, track, turnouts, etc. Backtrack yourself and disconnect the last things you did until it clears. The symptoms are strange, but that happens sometimes. Its almost like something is crossed up, but not an actual short. (I run across that sometimes with block detection, but not on regular track layout.):)
Click to expand...

Its been a while. Being summer time, I haven't been doing much, more of a winter project for me. I really can't think of anything I've done, that this started happening after the point. I don't have any block detection so like you say, just regular track layout.

WCWBrassHat said:
Eric,

What are you using to provide power to the DB150? Does it provide 5+amps?

What gage buss wire are you using? How long is your power buss? I have found on my layout that once I got over 30' from the DB150 the quarter test would not work at the end of buss. Start near the DB150 and do the quarter test. Move progressively further away and see if it stops tripping? If it doesn't trip immediately, remove the quarter. You will need to add short circuit protection like a DCC Specialties PSX or a Digitrax PM42 to provide the short circuit protection at the distance.
Click to expand...

I have quite a bit of bus wiring. Certainly over 30'. However, I tried the quarter test at the closest point I can to the DB150. As well as at the furthest. I think one of the things I will test is connect the db150 to my test track only, which is not currently connected in anyway, and see if I can short that out.

Thanks a bunch guys, hopefully I can get this sorted out rather easily.
 
Eric: If the quarter test doesn't work at the command center, particularly when on a short section of track only, then you need to call Digitrax. You will find them very willing to help.
FYI: You can check voltage rail-to-rail by following Digitrax "how-to" or directly if you have a digital meter that reads RMS voltage values. Actually, you can read the rail voltage with any meter: It won't be accurate in value, but it will allow you to make a comparison of these values from point A to B to C and see if there is a decrease.

NOTE about bus wiring: Something that many do wrong on a long power run is to feed off of one long bus that is fed at one end by the command unit. If you tap the middle of the bus with a feed from the command unit, then you have divided the current into two (or more) sections and you will see better power distribution. Glenn's suggestion of a PM42 actually does this division of power by separating the track layout into individual power districts. My suggestion is with ~30feet of bus, connect the command module output to the middle of this bus, not at the end. Doubtful that this is your problem, but it will help your operation on those busy traffic days:).
 
Yeah, Rex, you're dead on. I guess right from the start I should've hooked it up to a single piece of track. It exhibited the same behavior there, so clearly the command station is at fault.

Although Digitrax did say they'd fixed it under it's 1 year warranty of course, they seemed less than helpful/interested when I contacted via email and phone. I was actually kinda disappointed. You guys here offered orders of magnitude more help than they even attempted to do.

Coincidentally, my bus is split about the middle, going in either direction directly from the DB 150.

Thanks for the help!
 
Eric, go to Digitrax and print out the form for repair. Follow instructions for repair. I think you have to call them and get a number for this repair then send it to them with full details. They may end up replacing the whole guts. Probably be gone for two to three weeks. Also, explain your disappointment in Digitrax having thought they were the best.;) They will come around.
I had a very intermittant problem with my DCS200 and sent it to them. They didn't find anything, but they replaced all the electronics, even with upgrade. ;) :) (Turns out the problem was at my end; the connector wires coming from my transformer were slightly loose and when they heated, they opened :eek::eek::D.)
 
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The unit is worth repairing, particularly if it is a simple and inexpensive fix. As Rex points out, they may surprise you and waive their fee if it is something that they have had to correct routinely when DB150's come in for servicing. IOW, if they know of a trouble spot, honourable people usually come clean and fix it for nothing. If it is a somewhat unique or uncommon problem, they will only charge you a few bucks...certainly much less than a whole new command station.

Just my thoughts. The sooner you get it to them and have it back, the sooner the winter rails sessions fall into place for you. :)

-Crandell
 
It was mailed immediately. Even though it's mostly a winter project since I have plenty of "summer hobbies", it certainly doesn't mean I don't get down there. ;-) So I'm eager to get it back, and working. In the mean time, I've already spent time time putting in feeders where they're needed, so it's all ready to go when I get it back.

My disappointment was the utter lack of any interest, as it seemed to me. The initial email they returned to me, was not even of remote help. In fact, it was a waste of my time to send them one, to their tech support email address. The phone call later was very lackluster as well, although at that point, things were much simpler since I had tested it on a single piece of track.

Hopefully it makes a quick return.
 
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